The multitude of the scholars opinion on matter constitutes a mark of development and scientific maturity as it is the outcome of effort persistence and self-denial for the sake of truth. Our Arab thought knew luminous examples of this phenomenon as it is a phenomenon that impacts the depth of our Islamic thought and among the examples of the phenomenon is the multiplicity of the grammatical opinion of the same scholar on the same issue as we find him going at one time towards one of the opinions and then tending at another time to another opinion for an argument that appeared to him. This research is based on the determination of this phenomenon with Abu Ali Al- Farsi who was known for his lofty scientific position in Arabic grammar and his books were truly a good model for knowing this intellectual life and our study endeavor to demonstrate the impact left by the transformation of the grammarian from his first saying in taking his other opinions and to stand on the most important factors calling for this transformation and we have taken the analytical approach and its procedures as tool in analysis and study and the research has reached a set of results were in forefront: Abu Ali Al Farsi has a distinguished scientific personality and he was not satisfied with presenting the grammatical dispute but rather we find him taking the position of the fair critic who builds his weighting on serious epistemological foundations and logical ones that take into account the linguistic and mental reality. Abu ALI Al -Farsi was clearly affected with his sheikh Ibn Al- SarrajWe followed him on a number of issues including his saying of literally of (not) and refusal antecedent its prediction and limited the addition of Ba to ( what) the Hijazi and the loss of many of Al-Farsis books prevented us from standing on many of his opinions including the Book of Letters and the Ticket.